<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <title>jQuery - $ is not defined</title>
    <script src="https://code.jquery.com/jquery-3.5.1.min.js"></script>
    <script>
$(document).ready(function(){
    $("button").click(function(){
        alert("jQuery is working perfectly.");
    });
});
</script>
</head>
<body>
<button type="button">Test jQuery Code</button>
</body>
</html>